Question

How do I know where to set the illuminator level when I scan my slides?

Answer

Each uScope model is calibrated (in air) at a specific objective illumination as shown in the following table. Typically, when scanning a slide, you need to use an illuminator setting slightly higher due to the light attenuation of the glass slide.

Higher numbers make the image brighter while lower numbers make the image darker.

• If the illumination is set too low, image data may be lost because the dark pixels are undersaturated and become black.
• If the illumination is set too high, image data may be lost because the light pixels are oversaturated and become white.

The following images illustrate this effect.

Illumination Level: Good

The illumination for this image is set to 35. The illumination controls and setting display in the bottom part of the browse window.

The detail level shown (in the indicated area in the upper-left part of the image) is good and isn't washed out (oversaturated).

It is easy to discern the tissue pattern in the lighter areas of the image.

The illumination for this image is set to an appropriate level.

If you want to make the image brighter, it may be better to use a filter sequence to increase brightness, contrast, and gamma than to increase the illumination level.

Illumination Level: Too Bright

The illumination for this image is set to 50. The illumination controls and setting display in the bottom part of the browse window.

The detail level shown (in the indicated area in the upper-left part of the image) is oversaturated. Image data is lost and lighter parts of the image will be white and appear to be empty of specimen.

The illumination for this image is set too bright and will result in washed-out images. Image data will be lost as a result.

While it is possible to use filter sequences to reduce the brightness, contrast, or gamma in an image, it is not possible to use filters to recover image data that is oversaturated. The oversaturated image has lost image data that may be vital to its interpretation.